Suppose the current price $($i$.$e$.,$ MSP$)$ of a product is $$3\mathrm{.}50,$ and at that price, the unit sales are $100,000.$ The manufacturer gives a $10\%$ promotional allowance and the total variable costs are $$1\mathrm{.}60($this number includes the promotional allowance$).$ How much is the promotional allowance?

$$0\mathrm{.}35$

$$1\mathrm{.}25$

$$1\mathrm{.}60$

Cannot be determined from the given information